The large fire in the Kentbruck-Portland Nelson Rd area in South West Victoria is continuing to challenge firefighters although they're hopeful of bringing it under control before Friday's expected hot weather.

Speaking on South West breakfast on Thursday morning, Incident Controller Andrew Morrow said they'd 'had a successful 24 hours' and were 'on track' to achieve their objective of bringing the fire under control.

He spoke about the backburning operations along Inkpot Rd and Heath Rd and described the wet boggy conditions which have made that backburning difficult.

The backburning will take in around 4,500 hectares bringing the total fire size to somewhere around 11,000 hectares.

Increased levels of smoke are expected today because of the backburning and other work going on around control lines, and reduced speed limits will apply on the Princes Highway between the Portland Casterton Rd and Dartmoor.

An inversion layer over the region is also expected to keep the smoke closer to the ground, adding to the amount of smoke in the area.

A community meeting will be held on Thursday morning at the Dartmoor Community Hall at 11am to discuss the backburning strategy and answer any questions locals may have.

Other closures still in place include the Winnap-Nelson Rd which is closed between the Portland-Nelson Rd and the Princes Highway at Winnap.

The Cobboboonee National Park is closed, including all camping areas.

The Glenelg River is also closed to canoeing and boating from the Princes Highway at Dartmoor to Skipworth Springs.